Neurofeedback is a form of biofeedback which uses either electroencephalograms or functional MRIs to measure brain activity. Sensors are placed on the scalp to determine which types of waves the brain is producing and the ratio between the types of waves. There are many techniques of neurofeedback, also known as neurobiofeedback, neurotherapy, and EEG biofeedback. The basic structure is that brain activity is measured displayed on a monitor. The patient is given tasks like simple games or concentration challenges which affect the waves being produced. When brain waves change favorably, the patient hears a pleasing tone or other sensory reward.